Base for electric lamps and similar devices



May 28, 1946. E. B. NOEL 2,401,228

BASE FOR ELECTRIC LAMPS AND SIMILAR DEVICES Filed Feb. 12, 1945 FIG]FIG.5

INVENTOR= EDWARD BL NOEL,

HIS ATTORNEY ing 9741.

Patented May 28 1946 BASE FOR ELECTRIC LAMPS AND SIMILAR DEVICES EdwardB. Noel, Cleveland Heights, Ohio, assignor to General Electric Company,a corporation oi New .York

Application February 12, 1945 Serial No. 577,519

3 Claims. (Cl. 176--32) This invention relates to the basing ofjuxtaposed ends oi electric tubes, and especially tube ends extendingside by side. Tubes to which a common base according to my invention isapplicable include both tubular electric incandescent lamps and electricdischarge tubes, which are commonly made of vitreous materials. Anelectric lighting tube ofglass bent to a U-form offers a particularexample of a bunch or cluster of parallel tube ends which mayadvantageously be provided with such a base. The aim of the invention isto provide a simple and convenient base that can be applied quickly andeconomically, and presents a good appearance. Various other features andadvantages of the invention will appear from the description of aspecies and form of embodiment, and from the drawing. 1

In the drawing, Fig. 1 is a tilted side view of a vitreous U-bentelectric discharge tube equipped with a base embodying the invention,which is shown partly broken away and in section; Fig. 2

are sectional views of the base by itself, at right angles to oneanother, taken as indicated by the lines and arrows 33 and. l4 in Figs.2 and 3, respectively; Fig. 5 is a fragmentary sectional view of thebase and associated tube ends, illustrating a stage of the basingoperation; and Fig. 6 is a similar view illustrating a variation in thebasing operation. a

Fig. 1 shows a base I applied to adjacent tube ends 2, 2 lying side byside, being the ends of a U-fbent vitreous tube 3 whose legs areapproximately parallel. A U-tube is one form suitable for the envelopeof a discharge lamp producing ultraviolet radiation of germicidalwave-length such as 2537 A., and for this purpose is of course made 01'glass permeable to such radiation, exemplified by the glass knowncommercially as Corn- As shown in Fig. 1, each of the tube ends 2 is ofordinary stem flare and pressed seal construction, with current leads 4,4 extending through the seal 5 inward into the tube, and with afilamentary electrode or cathode 6 connected between the inleads. Thiselectrode may consist of a coil or coiled coil of fine tungsten wireactivated with a coating or filling of alkaline earth oxides such as amixture including barium and strontium oxides. The inner ends I, I ofthe leadwires 4, 4 beyond their attachment to the filament 8 may serveas auxiliary anodes. The tube 3 may contain a filling or starting gassuch as one of the inert rare gases, like argon I at a pressure of 8 /2nnn'., and a charge of vaporizable and ionizable working substance likemencury is also indicated by a droplet 8. The amount of mercury ispreferably less than will vaporize during operation, thus assuring anunsaturated its bottom or end web holes I0, ill to accommo date the tubeends'2, 2. Such a cup-like part H can easily be formed out of sheetmetal by diepressing and punching. Differently described, the element II comprises a single base shell shaped to s an appropriate cross sectionto accommodate the a is a plan view of .the base by itself; Figs. 3 and4 cluster or pair of tube ends 2, 2 with some clearance, and also,across the shell end thatis uppermost in Figs. 1 and 2, a web l2 piercedwith holes Hi, It conformable to the tube ends in shape and,approximately, in size. As shown, the holes It, In are circular and of adiameter Just over the maximum limit of tolerance for variation of ithaving their upper ends fixed in the dia-w phragm, and'exposed at theouter side of the diaphragm. As shown, there are two pairs of the pinsI6 of different sizes, centered on a circle in positions that adapt themto known standard electric sockets. It may most simply be provided bymaking the whole diaphragm ll of insulating material such as plastic orvulcanized fiber and riveting the contacts it into holes in thisdiaphragm.

As shown in Figs. 1, 3, and 4, the end wall or diaphragm i4 isperipherally seated at and in l the shell mouth IS with a shoulderedengagement.

It is simplest to provide the shoulder in the mouth I5, rather than onthe edge of the diaphragm it, as by an internal rabbett I! formed byexpanding the shell mouth somewhat. The diaphragm It may be secured inits seat by inward deformation of the shell wall, which as shown inFigs. 1, 3, and 4 is turned or flanged inward all around at [8.

As shown in Fig. 1, the tube ends 2, 2 may be secured in the base I bymeans of cement l9,

such as a body of ordinary, standard, thermo setting incandescent lampbasing cement adherent to the interior of the shell H as well as to theseveral tube ends 2, 2. In practice, this Such insulation of thecontacts cement Il may be smeared into the interior of the base throughthe holes l0, in before inserting and pushing home the tube ends 2, 2and attaching their leads 4, 4 to the base contacts I8 as shown. Theamount oi cement I! need be only enough to insure its adhesion to thetube ends 2, 2 adequately, without filling the interior oi the basecompletely.

It is convenient to heat the base I to cure or set the cement I! withthe assembly in base-up position as shown in Fig. 5, or on its side asin Fig. 6, rather than base-down as in Fig. 1. In this connection, thelips i3, i3 are 01. great service in preventing appreciable leakage oicement out through the holes Ill, III around the tube ends I, 2, evenwhen the base I is inverted as in Fig 5, and even when the basing cementis used at its freshest, when it is most fluid and has the lowestviscosity. I have found that notwithstanding the clearances around thetube ends 2, 2 when they are at the smallest limit of tolerance, theadhesion of the cement to the juxtaposed surfaces 2, l2 and its surfacetension prevent its flowing out through the clearances, even when itsfluidity is at the maximum of the practical range of variation. Asillustrative of good practice, I may mention that for tube ends 2, 2 ofnominal inch extemai diameter, which may actually vary from .500 inch'to.550 inch, holes ll of substantially 0.57 inch diameter with lips I!having an inward projection or height of 1: inch are satisfactory withthe ordinary basing cement above mentioned.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The combination of electric lamp tube ends disposed side by side; asingle sheet metal base shell having across one end thereof an integralweb with holes therein conformable to the several tube ends, whichextend into the interior of said shell through said holes; a diaphragmclosing the otherend of said shell, with insulatively separated contactterminals for said tube ends carried by said diaphragm; and a body ofcement in said base shell adherent both to its interior and to theseveral tube ends.

2. A base for a plurality of'electric lamp tube ends disposed side byside. said base comprising a sheet metal cup shaped to accommodate thetube ends and having in its bottom web holes corresponding andconformable to said tube ends; and a diaphragm secured across andclosing the mouth of said cup, with insulatively separated contactterminals for the tube ends carried by said diaphrar'n.

3. A base for a plurality of electric lamp tube ends disposed side byside. said base comprising a sheet metal cup shaped to accommodate thetube ends and having in its bottom web holes corresponding andconformable to said tube ends, with inturned lips around said holes; aninsulative diaphragm seated with shouldered engagement in the mouth oisaid cup; and insulativeiy separated contact pins for the tube endsfixed in said diaphragm and exposed at its outer side.

EDWARD LB. NOEL.

